There is a telescopic type steering apparatus configured to adjust the telescopic position of the steering wheel by fitting the outer column and the inner column together slidably in the axial direction. Further, as disclosed in Japanese Patent Application Laid-Open No. 2010-208588, there is a tilt/telescopic type steering apparatus configured to adjust both of the telescopic position and a tilt position of the steering wheel.
In this type of steering apparatus, after completing the adjustment of the telescopic position, an inner periphery of the outer column clamps an outer periphery of the inner column by reducing a diameter of an outer column having a slit, thus clamping the inner column so that the outer column is disabled from relatively moving in the axial direction. Further, a lower steering shaft is fitted such as being spline-fitted to an upper steering shaft mounted with a steering wheel on the rear side of the vehicle body to enable a telescopic movement, thereby transferring rotations of the steering wheel to a steering gear and thus changing a turning angle of traveling wheels.
Before mounting this type of steering apparatus on the vehicle body, to be specific, in a state before a vehicle body fitting bracket is fitted to the vehicle body, e.g., when delivering the steering apparatus or when assembling a column cover, it might happen that the inner column is released from the telescopic clamping by the outer column in the case of operating an operation lever by mistake. In this state, when pulling the steering wheel toward the rear side of the vehicle body, the outer column escapes from the inner column together with the vehicle body fitting bracket, with the result that the steering shaft is released from the spline-fitting as the case may be.
In an electric power steering apparatus, an input shaft on the side of the steering wheel is connected via a torsion bar to an output shaft on the side of the traveling wheels, a torque sensor detects a distortion of the torsion bar, torque acting on the torsion bar is detected from a result of this distortion, and a required steering assist force is given to the output shaft by driving the electric motor.
Therefore, it is necessary that a neutral state of the upper steering shaft on the side of the steering wheel is made coincident highly accurately with a neutral state of the lower steering shaft on the side of the traveling wheels, and assembling is attained by making a phase of the spline of the upper steering shaft to which the rotations of the steering wheel are transferred coincident highly accurately with a phase of the spline of the lower steering shaft to which the rotations of the traveling wheels are transferred. Accordingly, if the steering shaft is once released from the spline-fitting, such a problem arises that there is a time-consuming operation of reassembling the upper steering shaft and the lower steering shaft together in a way that makes the spline phases thereof coincident with each other at the high accuracy.